The present invention relates to a breaking up device for use in straining tuns to obtain wort in the production of beer, with arms fastened horizontally to an upright, motor-powered shaft, each supporting a row of cutting blades, on the bottom ends of which are fastened cutting shoes, in order to loosen up or disaggregate the brewer's grain cakes forming on the screen or filter base of the straining tun, with the clarifying process, along different circular paths.
During a clarifying process to obtain wort for the production of beer, the brewer's grain cake is packed over the screen or filter base of the straining tun, so that prolonged or repeated loosening up of the brewer's grain is required to obtain more wort. This is attained with a cutting device built into the straining tun, which has a plurality of horizontal arms on an upright, motor-powered shaft, each supporting a row of cutting blades projecting downwardly. Thus it is known to fasten a plow-like cutting shoe at the bottom of each cutting blade, and certainly at such a level that these cutting shoes work when the breaking up device is rotating approximately 5-10 mm over the screen of filter base such that they loosen or break up the packed brewer's grain cakes along circular paths. In order to improve this loosening effect, it is already known to arrange the cutting blades with the arms radially offset from each other, so that they produce additional cutting lines with different radii.
However, for an optimum loosening up of the brewer's grain cakes, the breaking up device used up to the present time has had to circulate may times. Since the velocity of circulation of the breaking up device is only 3-5 m per minute, much time has been required for this step. In order to avoid this drawback, i.e., for fewer rotations to be sufficient, the number of arms supporting cutting blades has already been raised to six. But this greater structural outlay is costly and the danger then arises that, because of the large number of cutting blades during circulation of the breaking up device, a "thrust" of the brewer's grain may occur, resulting in a negative influence or even destruction of the filter function of this layer. The wort which is still produced then has a very undesirable turbidity. This drawback can also occur with breaking up devices of which the cutting blades support radial cutting strips at their ends.